The Surface Al2o3 Coating And Bulk Zr Doping Drastically Improve The Voltage Fade and Cycling Stability Of Li(Ni0.8mn0.1co0.1)O2 Cathode Materials

One of the major hurdles of the Ni-rich layered oxides (NLOs) in making lithium-ion batteries is their low cycling stability, especially for the NLOs with Ni content ≥ 60%; such NLOs have clear drawbacks including severely fading of capacities and impedance increase during cycling. Two promising surface and bulk modifications of such NLOs to alleviate the drawbacks are: (1) the surface coatings by electrochemically inert inorganic compounds and/or (2) the lattice doping by cations. In this work, isopropanol alcoholysis has been used to achieve uniform surface Al2O3 coating on one of NLOs: LiNi0.8Co0.1Mn0.1O2 (NCM811). The bulk Zr4+ doping and surface Al2O3 coating have been realized after annealing at ≥800 °C, which enhance the specific capacity of discharge and cycling life of the NCM@Al2O3+Zr active material, and effectively suppress the voltage attenuation during cycling process. The main finding of this work is the enhanced cycling stability and the diminished impedance of the coated/doped NCM811, being conferred by a synergetic effect of the Al2O3 coating and the Zr4+ doping.